This site is the blogging component for my main site Crank Astronomy (formerly "Dealing with Creationism in Astronomy"). It will provide a more interactive component for discussion of the main site content. I will also use this blog to comment on work in progress for the main site, news events, and other pseudoscience-related issues.

In Peratt's model, galaxies form at the intersection of large-scale (many megaparsecs long) Birkeland currents. This model had the interesting feature that it formed objects that resembled spiral galaxies and they exhibited rotation profiles similar to those observed for spiral galaxies, without the need for dark matter needed in the standard Big Bang cosmology. These characteristics were observed in both plasma experiments and in particle simulations.

So why isn't the Peratt model the accepted model for galaxy formation? Because galaxies are not defined by rotation curves alone. Peratt's model made a number of other predictions that failed significantly.

The Birkeland currents, by definition, have magnetic fields parallel to their direction of flow. These currents will also will generate their own magnetic field, just like any other current. However, the field along the path of the current needs to be much stronger than the self-generated field or the stream will be unstable. The electrons will trace out circular or helical paths due to the magnetic field as they move along the current stream. But in circular motion, the electrons will accelerate, and therefore radiate. This radiation is called cyclotron (in the non-relativistic case) or more generally, synchrotron radiation.

So these Birkeland currents will be expected to emit synchrotron radiation. Dr. Peratt calculated just how much they would be expected to radiate and obtained values of energy output on the same order of magnitude as the measured flux of the cosmic microwave background radiation[4].

But there was a problem. Cyclotron emission for electrons of a fixed energy emits energy in discrete spectral lines corresponding to the cyclotron frequency and harmonics (integer multiples). The cosmic microwave background is a broad smooth blackbody curve, very different from the sharp line spectra of cyclotron radiation.

But we don't expect the electrons to be monoenergetic nor the magnetic field their in to be completely uniform. Peratt assumed a 'bithermal' electron velocity distribution, where the mean electron motion would correspond to one temperature along their direction of motion, but another temperature perpendicular to their direction of motion. [Note that the commenter 'Anaconda' in this thread (link) dismisses the use of 'thermal synchrotron' distribution because I could not demonstrate it had been seen under laboratory conditions. I assume he would condemn Peratt for invoking thermal synchrotron radiation as well. Actually, 'thermal synchrotron radiation' relies on the correctness of two concepts: the Poynting vector definition of electromagnetic energy, and Maxwell's equations. It basically says that the radiation flux from a collection of particles, emitting incoherently, is the sum of the fluxes of radiation from individual particles.]

With a distribution of electron energies and magnetic field strengths, the peaks of the synchrotron radiation broaden into 'bumps'. Peratt found that by assuming the CMB was created by the sum of the emission of many of these current streams, the shape of the CMB spectrum could be matched over frequencies up to 100GHz. But he needed many filaments to do this, about 10^31[4].

Peratt's model clearly requires synchrotron emission from the current streams powering the galaxies and his own calculations show that instruments such as COBE and WMAP have sufficient sensitivity to see them.

Peratt reports that the mean lengths of these current streams must be on the order of 350 MEGAPARSECS. This means that the currents driving the nearer galaxies, such as M31 & M33 should be clearly visible in the raw WMAP data, before the foreground processing is even performed!

Here's a snapshot of the M31 and M33 superimposed on the WMAP CMB map using Google Earth in Sky mode. (click to enlarge)

We can also check out the nearby Virgo cluster of galaxies.

Where are the current streams to power these galaxies!? The streams for these nearer galaxies and clusters should lie over all the other more distant streams. At a distance of 600,000 pc for M31, a 350Mpc long filament should appear to be 2*arctan((350e6 pc/2)/0.6e6 pc) or 180 degrees across. Even if not strictly linear, this structure should show up! Where is it? All we see are random blobs, more consistent with noise (and consistent with the Big Bang interpretation) than current streams.

Why should I , or anyone else, believe these galactic-scale currents exist when Peratt's own predictions for them fail?

Peratt own calculations demonstrated that the flux from these currents was comparable to the intensity of the cosmic microwave background radiation [4] and he even expected to see a ''”spaghetti” of radiating filaments surrounding the viewer'[5].

I have heard reports that in addition to the current streams not being visible, the Peratt model had serious difficulty reproducing the fluctuations of the CMB at the level detected (10^-5), though I have yet to find where this result may have actually been published.

Perhaps the synchrotron radiation is being beamed?

This happens in pulsar emission, so it could be happening in the current stream and is not beaming directly towards us? There are several problems with this scenario:

Synchrotron radiation is beamed in the direction of motion. In the case of electrons moving in circular orbits, the beam sweeps out a full 360 degrees in the plane of motion, much like the headlight of a motorcycle moving around a circular track. The emission could be confined to a plane, but the plane would be aligned with it's normal (perpendicular) vector along a circle around the current stream. The beaming would still sweep over all directions outbound from the current stream.

To explain the galaxy distribution, these currents must be pointed all over the sky in random directions. This means the plane of the electron motion will be randomly distributed as well. The odds that we are out of the coverage of all these emitting electrons becomes slim.

Peratt only needs 30keV electrons to generate the galaxies in his models. This makes the electrons non-relativistic, so the beam of light emission is very broad, not narrow as would be the case for relativistic electrons. The emission would be strong in many directions so beaming is not a problem.

Why Don't We See the SDSS Filaments in WMAP?

In his rebuttal (link, The WMAP Map, page 10) to my previous paper (link), Dr. Scott tries to deflect this criticism of the Peratt model by asking why don't we see the filaments of galaxies reported in the large-scale galaxy surveys such as 2dFRS or SDSS against the CMB maps (see Large-scale Structure of the Cosmos).

In mainstream cosmology, these filaments are NOT due to electric currents. Computer simulations of structure formation are perfectly capable of forming filamentary structures without the need for them to be powered by currents. You can see for yourself the results of some of these simulations at the website for “Simulating the joint evolution of quasars, galaxies and their large-scale distribution”. This group even makes their simulation code, called Gadget, generally available so others may evaluate it.

In dark matter cosmologies, these filaments are NOT expected to be strong sources of emission over a broad range of wavelengths such as synchrotron radiation. In order to be seen by WMAP, these filaments would need to have sufficient emission or absorption in the radio frequencies observed by WMAP. Since these filaments would be largely atomic hydrogen, their major emission and absorption in radio would occur at a frequency of 1.420 GHz (wavelength = 21 cm). This frequency, as well as others frequencies of emission and absorption expected by atomic hydrogen, are well outside the frequency of WMAP observations (23-94 GHz). Atomic hydrogen is largely transparent in the WMAP frequency range[6].

There are a host of additional problems with the Peratt model which I cannot find addressed anywhere.

What powers these cosmic-scale Birkeland currents? What is the origin of the EMF that drives them? Are there any laboratory or theoretical models that such currents of such size and magnitude could be driven by turbulence?

With a mean length of ~350 Megaparsecs for Peratt's filaments, the ends of these filaments should be visible in our current galaxy surveys so we should be able to see the source of the EMF and magnetic field which maintain them. Not only do we not see any objects that could fulfill this role, even Don Scott admitted that they did not know the source of these Birkeland current systems. These invisible, physics-defying current sources must be far more complex than single weakly interacting particles proposed as Dark Matter. Because their predicted emission is well within the sensitivity of our present day instruments, these invisible current sources are a far larger problem for EU than Dark Matter is for the standard cosmology.

With currents driven by 30 keV electrons in Peratt's simulations, this is more than enough energy to ionize intergalactic neutral hydrogen (ionization potential = 13.6 eV). Recombination (electron and proton reforming the hydrogen atom) will emit photons at these energies, in the ultraviolet. Cosmological redshift could move this emission into the visible range for galaxies at high redshift (z>4) values. More distant and sensitive surveys should see these currents in the range of optical emission!

I'd like to thank some members of the WMAP team for their helpful input.

6 comments:

There are quite a few, quite separate, sets of inconsistencies between Peratt's model - as published in papers he authored - and well-established astronomical observations.

In later comments I'll go through some of these in detail (if any reader is interested), and also give links to open discussions of (some) of these in internet fora.

In no particular order, and not in any way intended to be a complete list (!):

* mismatch between galaxy types (spiral vs elliptical etc), the ages of the stellar populations, and their relative number

* in spirals, rotation curves for stars, neutral gas, and ionised plasmas are the same (with some possible exceptions a long way out); in Peratt's model this cannot happen (many reasons)

* few, if any, spirals have a 'double bulge' morphology; in Peratt's model, nearly all should

* a great many aspects of the characteristics of what we today call AGNs are misaligned, or completely inconsistent, with Peratt's model (this is partly due to the enormous advance in our understanding of AGNs since 1986 ... Peratt's publications since then have conspicuosly failed to incorporate this new understanding).

On the outside chance that the WMAP data is not cosmological, it is clearly not evidence for the Peratt model either. Peratt's own estimates of the current streams microwave emission mean they should be visible even before the background subtractions are performed.

I've added these papers to my list. Maybe I'll get a chance to read them.

S.J. Crothers: the first is, indeed, about WMAP. However, the second is about COBE, and the third about Planck. All are from the journal "Progress in Physics". In light of your earlier comment elsewhere (in response to one of mine), may I ask if you consider this journal to be a scientific forum? If so, why?

Turning to the documents themselves. Your comment suggests that you think the content is sound ("which reveal"), do you? If so, would you be prepared to defend it, on an open internet discussion forum?

FWIW, I think all three reveal nothing more than the author's lack of understanding of the subject (but I'd be happy to discuss further).

Is it to be assumed that electrons within a Birkeland current move in circular and spiraling motions? A circular motion at least, would indicate that the internally induced magnetic fields are more important than the ones driving the Birkeland current in the first place. Now, the Birkeland currents are per definition initially field alligned, and the additional induced magnetic fields (a collective cylindrical one), would be surrounding the Birkeland current, seen from a classical point of view. However, it is the Debye shielding that prevents the effect you propose are happening (that otherwise would produce cyclotron radiation). For this reason, it seems likely that Birkeland currents can be in "dark mode" until they interact with considerable densities of plasmas or gases, seen as glow mode in various wavelengths (double helix above Milkyway centre?) or as auroras.

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I obtained my doctorate in physics and astronomy in 1994. I currently work in scientific data visualization for the media and public outreach. For more information on how I became involved in the creationism issue, visit my main page